rosette strain gauge

A single-axis gauge measures strain in one direction. A rosette combines three sensing elements on the same carrier, oriented at known angles (often 0°, 45°, 90°). That lets you calculate the principal strains and their directions—information you lose with a single gauge. In geotechnical work, this matters when lining stress or rock bolt loads aren’t aligned with obvious tunnel axes.

It depends on the surface porosity and moisture. For dry concrete, cyanoacrylate adhesives bond well and cure fast. If the surface is damp or you expect thermal cycling, two-part epoxy gives better long-term stability. Kingmach includes a general adhesive guide with each shipment, but we recommend testing a sample on your actual concrete mix before production installation.

Yes. Standard resistances are 120 Ω and 350 Ω, with grid lengths from 3 mm to 10 mm, but we’ve supplied shorter grids for small-scale lab specimens and longer ones for coarse-aggregate concrete. Customizations add a few weeks to lead time, so we typically ask customers to order early in the project.

Most three-element rosettes use a common shared lead for excitation, so you end up with six wires for a quarter-bridge setup per element, but exact wiring depends on the gauge circuit. Rosettes for full-bridge connections cut the wire count. Our junction boxes are pre-labeled and match our own dataloggers, so the manual walks you through it step by step—we also offer remote video calls if the diagram isn’t cooperating.

They’re designed for it. The polyimide carrier and constantan foil withstand years of humidity and temperature swings if protected from direct water flow. We’ve had gauges in a hydroelectric tunnel read stable for over six years. The bigger variable is usually cable protection and corrosion at the terminal strip; we recommend stainless steel terminal boxes for permanent installations.